Electron discharge devices



March 22, 1966 J. 5. BAILEY ETAL 3,242,253

ELECTRON DISCHARGE DEVICES Filed Aug. 2, 1963 -28 INVENTORS 1701 e fiz'Ze 25 211 2215 c zna E3} 97 w y- United States Patent 3,242,253ELECTRON DISCHARGE DEVICES James S. Bailey, Chicago, and Henry HSchmalz, Deerfield, Ill., assignors to The Rauland Corporation, Chicago,III., a corporation of Illinois Filed Aug. 2, 1963, Ser. No. 299,578 3Claims. (Cl. 174-5058) This invention relates to electron dischargedevices of the type having evacuated sealed containers such as cathoderay tube-s, and more particularly toa stem for such devices.

Electron devices such as television display tubes usually have anenvelope consisting of a funnel with a fluoroescent on its face and anarrow neck portion which contains an electron gun structure. A stem isused for sealing the end of the neck in order that the envelope may beevacuated and in addition includes lead-in wires which are coupled tothe electron gun.

Such a stem includes a disc-like press of glass which is hermeticallysealed at its edge to the end of the neck of the envelope. The press hasa central opening which is afiixed to an exhaust tube, and lead-in wiresare embedded in the press around the exhaust tube and its centralopening. The electron gun assembly is then supported inside the envelopeby the lead-in wires extending through the press.

In a system of this type is is a major problem to eliminate leakagepaths which occur along the lead-in wires allowing air to enter theevacuated tube, thereby destroying the tubes effectiveness. Normally inthe past, a glass pipe has been placed around each lead-in wire as itenters and leaves the press in order to effectively lengthen the portionof the lead-in wire which is sealed to the press. This preventivemeasure, however, has the disadvantage .that during the manufacturingprocess, movement of the lead-in wire may occur and cause a p'ip tobreak or chip, which in turn produces an air leakage path; depending onthe configuration of the pip, a reverse curve is usually present whichmakes it more susceptible to breakage, since stress concentrations maytend to build up at these points.

If the press is made thicker to provide a longer leakage path, heattransfer problems with the attendant build up of stress concentrations,arise in conjunction with the making of the press itself. In addition,ideally the edge of the press should be of approximately the samethickness as the tube neck to obtain a good seal between the two.

It is, therefore, a major object of this invention to provide animproved stem for an electron discharge device.

It is another object of this invention to provide a stem which obviatesthe above defects.

It is still another object .to provide a stern which eliminates airleakage path-s.

It is yet another object to provide a stem in which the build up ofstress concentration is prevented.

In accordance with the invention, a cathode ray tube having an envelopewith an elongated neck portion comprises a disc-like glass presshermetically sealed at its edge to the neck portion of the envelope ofthe cathode ray tube. The press has a central exhaust opening which issealed to, and communicates with, an exhaust tube, and the press is alsoconstructed to have a rim portion of a predetermined uniform thicknessextending inwardly (from its outer edge while an integral thickerannular por- 3 ,242,253 Patented Mar. 22, 1966 tion extends inwardlyfrom the rim portion to the exhaust tube, the surfaces of the rimportion and the thicker portion on the side of the press facing theexhaust tube being flat and parallel one to the other. Metal lead-inwires extend through the thicker annular portion of the press in spacedrelation about the central exhaust opening and are hermetically sealedto the press. The press is further provided with individualsubstantially conicall-ly tapered recesses around the lead-in wires withthe glass of the press flaring gradually outwardly from recessed contactwith the lead-in wires, and the lead-in wires are spaced from the glass,and thus free to flex, within the recesses.

The features of the present invention, which are believed to be novelare set forth with particularity in the appended claims. Theorganization and manner of operation of the invention, together withfurther objects and advantages thereof, may best be understood byreference to the following description taken in connection with theaccompanying drawing in the several figures of which like referencenumerals identify like elements, and in which:

FIGURE 1 is a fragmentary perspective view partly cut away, of anelectron device embodying the present invention;

FIGURE 2 is an enlarged sideview, partly in crosssection, of a portionof the device of FIGURE 1; and

FIGURE 3 is a partial cross-sectional view of a fixture used in sealingin a stem embodying the present invention.

In FIGURE 1 a television display tube has an envelope 10 which comprisesa funnel 11 with a phosphor coated faceplate (not shown) and a neckportion 12. A stem 14 is sealed to the envelope at the end or terminalportion of neck 12 and has mounted on it an electron gun structure 15. Aconventional pin base 13 is cemented to the end of neck 12.

Referring now to both FIGURE 1 and FIGURE 2, which shows a detailed Viewof stem 14, the stem includes a disc-like press 17 which may beconstructed of glass, for example, sealed at its edge 18 to the end orterminal portion of neck 12. As illustrated, the thickness of the pressat its edge substantially matches the thickness of neck 12. The pressincludes a central exhaust opening 19 which communicates with an exhausttube 2'0 sealed to the press. This exhaust tube is utilized only duringthe construction of the electron device and is sealed off after exhaustas shown, in a manner well known in the art. Lead-in wires 22 arehermetically sealed into press 17 and spaced around opening 19. Aroundeach lead-in wire is placed a glass pip 23 on the inside of the pressfacing the gun structure to increase the length of the seal between theglass and lead-in wires and to increase the internal electrical leakagepaths. Pips 23 are an integral portion of press 17 and are formedconcurrently with the press structure.

In accordance with the invention, an annular-portion 24 encompasseslead-in wires 22 and is relatively thicker than the portion of press 17contacting neck 13. For example, in a stem for achieving the advantageof the invention in television picture tubes, edge 18 of the press maybe .080 inch thick while annular portion 24 may be approximately .105inch thick. The surface 25 of annular portion 24 which is on the sameside of press 17 as exhaust tube 20, has a substantially planarconfiguration as illustrated; that is, the surface is substantiallylevel and flat. More specifically, thicker annular portion 24 includesan abrupt step 26 which is utilized as the transition between thin outerportion and the thick inner portion 24 of press 17. Wholly re-entrantseals 27, as distinguished from the provision of pips in priorconstructions, are provided around each lead 22 for greater resistanceto chipping if the lead is bent. Step 26 may be modified to provide asmoother transition between the thick and thin portion of the presswithout losing many of the novel advantages of the invention, but anabrupt step is useful in one aspect to be described below.

Thicker inner portion 24, provides a seal for lead-in wires 22 which ismore effective than prior art seals for several reasons. First, theelimination of a pip on the exterior surface 25 eliminates anypossibility of cracking the entire pip due to the relatively vigorousflexing of the leads which may take place during the construction of thetube. However, the length of the glass seal is still sufficiently long,to prevent air leakage paths due to the step type construction. Thebuild up of stress concentrations on or near the surface 25 isprevented, since its substantially planar configuration eliminatesreverse angle curves which are inherent in the previously employed piptype constructions. Lastly the matching of press 17 to the relativelythin tube neck is facilitated as a result of the novel construction.

As mentioned above, annular portion 24 may be formed by using either anabrupt step 25 or a relatively smooth transition. However, the abruptstep is advantageous in locating the system in relation to the tubeenvelope during mating of the two. In FIGURE 3, stem 14 is retained in acylindrical jig 28 having a flared out end portion 29 which is adaptedfor mating with step 26. The flared end portion 29 accurately locatesstem 14 on fixture 28. Tube envelope is placed in second jig (not shown)which is aligned with jig 28 with tube neck 12 slipping over stem 14.Thus, stem 14 is accurately lo cated by means of jig 28 and step 26 inrelation to tube envelope 10. Both the stem and tube are rotatedtogether at the same speed, subjected to a flame 30, and sea-led in amanner well known in the art to form a completed cathode ray tube.

The invention as described provides an improved stem which by its novelconstruction eliminates any possib-ilty of the creation of air leakagepaths and furthermore accurately locates the stem on the tube.

While a particular embodiment of the present invention has been shownand described, it is apparent that various changes and modifications maybe made, and it it there-fore intended in the following claims to coverall such modifications and changes as may fall within the true spiritand scope of this invention.

We claim:

1. A cathode ray tube having an envelope with an elongated cylindricalneck comprising:

a disc-shaped glass press hermetically sealed about its outer edge tothe outer end of said neck;

means defining an exhaust opening extending through the central portionof said press;

an externally protruding exhaust tube sealed to said press andcommunicating with said exhaust openmg;

said press having a rim portion of a predetermined uniform thicknessextending inwardly from said outer edge and further having an integralthicker ex :ternally stepped annular portion extending inwardly fromsaid rim portion to said exhaust tube, the surfaces of said rim portionand said thicker portion on the side of said press facing said exhausttube being flat and parallel one to the other;

flexible metal lead-in wires extending through and hermetically sealedto said thicker annular portion of said press with said wires beingcircumferentially spaced around said exhaust opening;

and means defining individual substantially conically i tapered openrecesses in said press around said leadin wires with the walls of saidrecesses flaring gradually outwardly from recessed contact with saidleadin Wires, said lead-in wires being spaced from said glass, and freeto flex, within said recesses.

2. A cathode ray tube having an envelope with an elongated cylindricalneck comprising:

a disc-shaped glass press hermetically sealed about its outer edge tothe outer end of said neck;

means defining a central exhaust opening in said press;

an externally protruding exhaust tube sealed to said press andcommunicating with said exhaust opensaid press having a rim portion of apredetermined uniform thickness extending inwardly from said outer edgeand further having a thicker externally stepped annular portionextending inwardly from said rim portion to said exhaust tube, thesurfaces of said rim portion and said thicker portion on the side ofsaid press facing said exhaust tube being flat and parallel one to theother;

flexible metal lead-in wire-s of uniform diameter extending through andhermetically sealed tosaid thicker annular portion of said press withsaid wires lbeing circumferentially spaced around said exhaust opening;

and means defining individual substantially conic-ally tapered openrecess about said lead-in wires in both the internal and externalsurfaces of said press with the walls of said recesses flaring graduallyoutwardly from recessed contact with said lead in wires, said lead-inwires being spaced from said glass, and free to flex, within saidrecesses.

3. A cathode ray tube having an envelope with an elongated cylindricalneck portion, in which is mounted an electron gun and which is of apredetermined interior diameter throughout its length except for anannular necked-down region at its outer end and located a predetermineddistance from said funnel portion with said necked down region beingformed incident to mounting said gun within said neck portion,comprising:

a disc-shaped glass press having a predetermined outer diameter lessthan said predetermined interior diameter and hermetically sealed aroundits outer edge to said necked-down region;

means defining a central exhaust opening in said press;

an externally protruding exhaust tube sealed to said press andcommunicating with said exhaust opening;

flexible metal lead-in wires extending through and hermetically sealedto said press with said wires being circumferentially spaced around saidexhaust opening;

said press having a rim portion of a predetermined uniform thicknessextending inwardly from said outer edge to the vicinity of said lead-inwire-s and further having an integral thicker externally stepped annularportion extending inwardly from said rim portion to said exhaust tube,said thicker portion encompassing said lead-in wires, and the surfacesof said rim portion and said thicker portion on the side of said pressfacing said exhaust tube being flat and parallel one to the other, thetransition region between said rim portion and said thicker portionbeing circular-1y concentric with the axis of the press and defining areference surface accurately spaced a preselected constant distance fromsaid funnel in correspondence with said predetermined distance and withsaid reference surface during assembly presenting an indexing abutmentenabling orientation of said press concentrically within said neckportion and at the position at which said necked-down region is formed;

and means defining individual substantially conically tapered openrecess about said lead-in wires in both the internal and externalsurfaces of said press with the Walls of said recesses flaning graduallyoutwardly from recessed contact with said lead-in Wires, said lead-inwires being spaced from said glass, and free rto flex, within saidrecesses.

References Cited by the Examiner UNITED STATES PATENTS 2,082,848 6/1937Rose 220-2 X 2,174,375 9/1939 Be-ggs 1745O X 2,205,502 6/1940 Tromp17450 X 2,235,135 3/1941 Andresen 17417 2,250,18 7/1941 Miller 174-50 X6 2,497,545 2/ 1950 Greiner 174-50 X 2,568,460 9/ 1951 NoLte 220-2 X2,904,456 9/ 1959 Nolte.

FOREIGN PATENTS 7 1,845 1/ 1941 Czechoslovakia. 964,806 2/1950 France.

ROBERT K. SCHAEFER, Primary Examiner.

0 DARRELL L. CLAY, JOHN F. BURNS,

W. B. FREDERICK, Examiners.

1. A CATHODE RAY TUBE HAVING AN ENVELOPE WITH AN ELONGATED CYLINDRICALNECK COMPRISING: A DISC-SHAPED GLASS PRESS HERMETICALLY SEALED ABOUT ITSOUTER EDGES TO THE OUTER END OF SAID NECK; MEANS DEFINING AN EXHAUSTOPENING EXTENDING THROUGH THE CENTRAL PORTION OF SAID PRESS; ANEXTERNALLY PROTRUDING EXHAUST TUBE SEALED TO SAID PRESS ANDCOMMUNICATING WITH SAID EXHAUST OPENING; SAID PRESS HAVING A RIM PORTIONOF A PREDETERMINED UNIFORM THICKNESS EXTENDING INWARDLY FROM SAID OUTEREDGE AND FURTHER HAVING AN INTEGRAL THICKER EXTERNALLY STEPPED ANNULARPORTION EXTENDING INWARDLY FROM SAID RIM PORTIONS TO SAID EXHAUST TUBE,THE SURFACES OF SAID RIM PORTION AND SAID THICKER PORTION ON THE SIDE OFSAID PRESS FACING SAID EXHAUST TUBE BEING FLAT AND PARALLEL ONE TO THEOTHER; FLEXIBLE METAL LEAD-IN WIRES EXTENDING THROUGH AND HERMETICALLYSEALED TO SAID THICKER ANNULAR PORTION OF SAID PRESS WITH SAID WIRESBEING CIRCUMFERENTIALLY SPACED AROUND SAID EXHAUST OPENING; AND MEANSDEFINING INDIVIDUAL SUBSTANTIALLY CONICALLY TAPERED OPEN RECESSES INSAID PRESS AROUND SAID LEADIN WIRES WITH THE WALLS OF SAID RECESSESFLARING GRADUALLY OUTWARDLY FROM RECESSED CONTACT WITH SAID LEADINWIRES, SAID LEAD-IN WIRES BEING SPACED FROM SAID GLASS, AND FREE TOFLEX, WITHIN SAID RECESSES.